<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
		div{
			display: inline;
			/* 块元素转换为行元素 */
			width: 500px;
			height: 500px;
		}
		span{
			display: block;
			/* 行元素转换为块 */
		}</style>
		<!-- div和span可以相互转换 -->
	</head>
	<body>
		<div>
			<div></div>
		</div>
	</body>
</html>
